In a search for causal relation or correlation between the structure and dynamics of biological membranes and physiological function, rod outer segment disc membranes of bovine retinae are isolated relatively intact and swollen into spherical vesicles in hypotonic media. Quasielastic, Electrophoretic and elastic light scattering in conjunction with Kerr effect measurements are performed on these vesicles in various ionic media. Prinicipal probes for structure are quasielastic and elastic light scatterings and those for dynamics are forward depolarized scattering (FDS) and Kerr effect. The independent variables of interest are photochemical states and ionic environment. Ion bound states are determined by electrophoretic mobility and photochemical states by optical absorbances of solubilized photopigments at lambda equals 498 nm and 400 nm. Membrane deformation characteristics are probed by spontaneous thermal fluctuations of spherical vesicles by the FDS method and by electric field induced deformation with the Kerr effect method. Bovine retinal disc membranes are ideally suited for the purpose because they can be swollen into a monodisperse suspension of spherical vesicles. There appears to be a thermal transition in the vicinity of physiological temperature relative to the deformation dynamics. There are two kinds of binding sites for Ca ion 2 on the membrane whereby the first one is a high affinity cooperative (second degree) one and the other is a low affinity non-cooperative one.